The article selected for review is How Galaxies Grow by Camille M. Carlisle. At the beginning of the essay, the author refers to the people who do not have enough knowledge when the topic of galaxies is brought up (Carlisle). A common perception among people is that bigger galaxies collide with one another and their cannibalistic fervour leads them to deform the smaller galaxies. Astronomers have been absorbed in studying the formation of the galaxy for 10 billion years now. The universe’s structure has always been a cause of piquing the astronomer’s interest. The author wishes to show the reader’s how exactly galaxies are formed and how they have been expanding over the years. Carlisle refers to the debate among astronomers over the concept of merging between galaxies. She wants to end the confusion that people have in their minds regarding the phenomenon that allows galaxies to become so massive.
The purpose of the article is to educate the reader on galaxy growth by explaining the science and theories behind galactic merges, and the roles multiple variables such as size ratios and gas amounts fulfil and the effects they have. Carlisle has included reports based on galaxies and their structures conducted by different astronomers. From the onset of the article, Carlisle mentions the process of merging and what effect it carries on the constellations. According to Carlisle, astronomers apprehend galaxy formation by looking at the creation of stars. Galaxies expand either by grabbing stars from elsewhere or by finding gas to make their own. The author proceeds to talk about the types of mergers that are present such as the minor merger that can wrap itself around a disk and make spaces for star formation. A crucial point that the author refers to is that the mergers aren’t the only source that allows galaxies to interact. Galaxies can suck up gas from its surrounding and pull other galaxies towards itself and in the process form a union.
The author proceeds to talk about star formation and how galaxies play an essential role in star formation. The different kinds of galaxies have different capacity to store gas that is needed for the birth of a star. An example of spiral galaxies is given in the article, and its function has been highlighted. In the latter half of the section, Carlisle further delves into the role played by mergers while talking about the growth of the Milky Way over the years. By studying the expansion of the Milky Way, the other isolated galaxies’ increase can be understood. An important aspect to be noted is that astronomers do not have unique instruments to study the galaxies thoroughly. A biologist will have tools that allow him or her to review the fossils while an astronomer does not.
The author has used a lot of scientific terms throughout the article that has not been explained thoroughly. While there have been references to what the different schools of astronomy think about the evolution of galaxies, the author could have done much better if the formation of stars and galaxies had been discussed in general before delving into what other astronomers had to say. However, the author did meet the requirements of the essay and fulfilled the purpose behind writing this article. The formation of galaxies was explained thoroughly at the start of the composition, and then the star formation and the role of mergers was described to help the readers understand how everything took place in space. The author did deviate here and there from her initial objective but it all tied down at the end.
- Carlisle, Camille. How Galaxies Grow. 2015, http://burro.case.edu/Academics/Astr151/HowGalaxiesGrow.pdf. Accessed 25 Feb 2018.